Facilities for sorting items such as parcels and packages are partially made up of systems referred to as sorters. These sorters are, for example, made up of carriages hingedly connected together to form a train that runs in a loop over a path forming a circuit. Generally speaking, the carriages form a chain with regular intervals. These sorting facilities are used especially in the retail industry, for preparing orders intended for points of sale or directly for customers.
The items are inserted by automatic loading stations onto the carriages or possibly onto roller conveyors. These carriages transport the items to outlets corresponding to pick-up areas or shipping areas. The passage of the item from the carriage to the outlet is currently an action that needs to be adjusted manually in order to ensure correct pick-up of the item and to avoid congestion or deterioration of the items during this transfer.
Sorting facilities are used to manage a broad range of items with weights of up to 50 kg and varied shapes or volumes, with carriage movement speeds of up to 3 m/s, Adjust in the ejection of the items is a complex operation.
To better understand the operation, the principle of ejecting a parcel from a sorting facility provided with a cross-belt carriage should be explained, even though the present invention is not limited in the scope of application thereof and allows the same operations in a facility using shoe-sorters or tilt-tray sorters, or any other known item-sorting device.
In order to eject an item from a cross-belt carriage, the cross-belt of the carriage is moved by a motor, which ejects the item perpendicularly or at a substantially acute angle with respect to the direction of travel of the carriage on the rolling belt of the facility. This ejection is initiated by an electronic device, referred to as trigger antenna, arranged facing each outlet.
The location of this device is defined in the study of the facility project and is adapted on site according to the actual position of the outlets. This ejection should make it possible to correctly position the items in the outlets, i.e. to give them a path that is compatible with the shape and the dimensions of the outlet. The outlets are receiving devices, for example roller conveyors, chutes, spiral chutes, baskets, etc.
When changing the type of items, it is sometimes necessary to carry out adjustments, via consecutive tests ejecting more or less large and more or less heavy items, in order to adjust the ejection position. Trigger antennas are commonly used, which transmit trigger orders to the carriage via infrared signals. Instead of these antennas, it is also possible to use the theoretical position expressed in pitch and in time, to indicate to a carriage the output at which the item should be ejected.
Adjustments may be carried out mechanically by moving the antenna for triggering the ejection, or by software, using a trigger offset (software delay at the time of unloading) as a function of the importance of the correction to be made. In order to proceed with the ballistics adjustment, it is convenient to pass items of different types and different characteristics through each of the outlets in order to adjust the trigger offset empirically until the operator or commissioning engineer observes acceptable behaviour. Only experience will allow a correct adjustment, which is based on the operator's sensations. The adjustment is not reproducible and is random from one facility to another.
Moreover, no reliable measurement can be used as a reference for subsequent inspection or for detecting a drift. No real-time diagnosis is possible, and this precludes any automatic error correction or alert. The adjustment of the ballistics of a sorter is thus a long and complex operation, which relies essentially on the experience of the commissioning engineer, since it is manual.